
Orthogonal plan with five parks
Early American model to curb fire/congestion
William Penn and surveyor Thomas Holme laid out Philadelphia in 1682 between two rivers as a generous gridiron of broad, regular streets punctuated by five public squares, conceived after London's plague and fire as a healthy, fire-resistant 'greene country towne.'
Philadelphia's plan was hugely influential in North America: the rational grid plus public squares became the default template for countless American cities. It linked the grid not to speculation alone but to an ideal of open, healthy, ordered settlement.
Realised and enduring; the grid and its five squares remain the framework of central Philadelphia, with the central square now occupied by City Hall.